Waveform analysis of differential graphs of reconstructed impedance cardiography from healthy individuals.

Purpose: The aim is to measure and analyze the wave amplitudes and time intervals of differential graphs of reconstructed impedance cardiography (RICG).

Methods: 180 adults with normal cardiac function between the ages of 18-78 were included in the study. Six mingled impedance changes on chest surface were simultaneously detected for each subject. The differential graphs of five impedance change components of RICG were obtained through waveform separation and software differentiation. The amplitudes of C, X, O, b waves and time intervals of Q-b and Q-C were measured and statistically analyzed.

Results: The amplitudes of C and X waves in PL, PR, AO, and that of C, O, b waves in LV and RV, all decrease as age increases. Wave amplitudes of the female group were bigger than those of the male group (p < .01), while the Q-C intervals of the female group were shorter than that of the male group (p < .01). Among five impedance change components, the wave amplitude of AO was larger than those of PL and PR (p < .01), and wave amplitudes of PL and PR were bigger than those of LV and RV (p < .01). Q-C intervals of LV and RV were longer than those of AO, PL and PR (p < .01), while the Q-b intervals of LV and RV were shorter than the Q-C intervals of AO, PL, and PR.

Conclusions: The differential graphs of RICG could reflect indirectly the physiological activities and pathological changes of the heart and of the large blood vessels in thorax.